JP2013006473A - Own vehicle signal discrimination device and tire air pressure detection device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more accurately discriminate signals transmitted from transmitters mounted in wheels of own vehicle from signals transmitted from another vehicle.SOLUTION: The transmitter 2 detects vehicle speed and is made to perform frame transmission after the lapse of prescribed time after the vehicle speed becomes first prescribed speed. A receiver 3 obtains vehicle speed information from an electronic control device handling the vehicle speed information, calculates a time interval taken from timing when the vehicle speed becomes the first prescribed speed on the basis of the obtained vehicle speed information to the reception of a frame and checks whether the time interval coincides with information about lapsed time included in the frame. On the basis of the check result, a transmission frame from each transmitter 2 of own vehicle is discriminated from a transmission frame from the other vehicle and ID registration of each transmitter 2 in own vehicle is performed.

Description

  The present invention relates to an own vehicle signal discriminating apparatus capable of discriminating between a signal transmitted from a transmitter attached to a wheel of the own vehicle and a signal transmitted from another vehicle, and in particular, a tire is attached. A direct type that detects tire pressure by directly attaching a transmitter equipped with a pressure sensor to the wheel, transmitting the detection result of the pressure sensor from the transmitter, and receiving it by a receiver attached to the vehicle body. It is suitable for application to a tire pressure detecting device.

  Conventionally, there is a direct type as one of tire pressure detecting devices. In this type of tire pressure detecting device, a transmitter equipped with a sensor such as a pressure sensor is directly attached to a wheel side to which a tire is attached. In addition, an antenna and a receiver are provided on the vehicle body side. When a detection signal from the sensor is transmitted from the transmitter, the detection signal is received by the receiver via the antenna, and tire pressure is detected. Done.

  In such a direct tire pressure detecting device, the data transmitted by the transmitter can be determined so that it can be determined whether the transmitted data belongs to the host vehicle and which wheel the transmitter is attached to. ID information (identification information) for discriminating whether the vehicle is a host vehicle or another vehicle and discriminating a wheel to which a transmitter is attached is individually given.

  In order to specify the position of the transmitter from the ID information included in the transmission data, the ID information of each transmitter needs to be registered in advance on the receiver side in association with the position of each wheel. For this reason, at the time of tire rotation, it is necessary to re-register the transmitter ID information and the wheel positional relationship with the receiver.

  On the other hand, a trigger signal is transmitted from a trigger device provided for each transmitter to the transmitter, and data including ID information is transmitted from the transmitter to the receiver in synchronization with the transmission. There has been proposed a method of registering the ID information of a machine and the positional relationship of wheels with a receiver (see Patent Document 1). There has also been proposed a method of reading the barcode attached to each transmitter and registering the ID information of the transmitter in the receiver. However, these methods have a problem that the number of man-hours for ID registration increases and the cost increases due to an increase in the number of parts such as a trigger machine and a barcode reader. In addition, there is a problem that, during tire rotation, ID information registration work occurs and work efficiency deteriorates. For this reason, there is a need for a system that can automatically perform ID information registration work for a transmitter.

  As such an automatic registration work, paying attention to the reception frequency in a certain period, it is determined that an ID signal with a high reception frequency among the received signals of a plurality of IDs is that of the own vehicle, and the ID There is a method for registering information (see Patent Document 2). In addition, using the information on the detection results of temperature and pressure included in the received signals of the plurality of IDs, for example, based on the fact that the temperature and pressure increase when the vehicle continues to travel, the detection result of the temperature and pressure is There is also a method of determining a signal correlated with a pattern as that of the own vehicle and registering the ID information (see Patent Document 3). Further, when receiving the received signal with an unknown ID, the reception strength of the signal (RSSI (Received Signal Strength Indicator) value) at the antenna attached to each wheel is measured, and based on the value, There is also a method of identifying the vehicle and registering its ID information (see Patent Document 4).

Japanese Patent No. 3212311 JP 2000-71726 A Japanese Patent No. 3661670 JP 2006-15895 A

  However, as in the method described in Patent Document 2, what distinguishes the host vehicle from other vehicles based on the signal reception frequency is accurate in a device with a low reception rate such as a direct tire pressure detection device. Is difficult to distinguish. That is, in a form in which radio waves are transmitted from a transmitter attached to each wheel, such as a direct tire pressure detection device, a signal may not be received depending on the tire angle, so the reception rate is low. . For this reason, when there is a parallel vehicle, the parallel vehicle may receive more frequently, and it is difficult to accurately distinguish between the host vehicle and the other vehicle.

  In addition, although the temperature inside the tire basically changes in response to the pressure change, the temperature change is slower than the pressure change and the temperature distribution exists in the tire. It does not correspond to. For this reason, as described in Patent Document 3, it is difficult to accurately discriminate between the host vehicle and the other vehicle even by a method using the temperature and pressure in the tire.

  In addition, since the signal reception intensity varies depending on the driving condition, the RSSI value of the signal transmitted from the parallel vehicle is a signal transmitted from the transmitter of the own vehicle in a situation where there is a parallel vehicle. May be larger than the RSSI value. For this reason, it is difficult to accurately discriminate between the host vehicle and the other vehicle even by the method using the RSSI value as in the method described in Patent Document 4.

  In view of the above, the present invention provides a host vehicle signal discriminating apparatus capable of more accurately discriminating between a signal transmitted from a transmitter attached to a wheel of the host vehicle and a signal transmitted from another vehicle, and the same An object of the present invention is to provide a tire air pressure detecting device including

  In order to achieve the above object, according to the first aspect of the present invention, the transmitter (2) provided on each of the four wheels (5a to 5d) detects the vehicle speed based on the rotation of the attached wheel. A detecting means (22), and the vehicle speed detected by the vehicle speed detecting means (22) reaches the first predetermined speed, and after a predetermined time has elapsed, the vehicle speed reaches the first predetermined speed in the frame. The receiver (3) has vehicle speed information acquisition means for acquiring vehicle speed information from an electronic control unit having vehicle speed information, storing information on the elapsed time until transmission, and from the vehicle speed information acquisition means Based on the time interval from when the vehicle speed reaches the first predetermined speed until the frame is received based on the acquired vehicle speed information and the elapsed time from when the predetermined vehicle speed stored in the frame is reached to when the frame is transmitted Whether or not the frame is transmitted from the transmitter (2) of the own vehicle attached to any of the four wheels (5a to 5d) by checking whether or not it matches the traveling pattern. It is characterized by matching.

  As described above, the transmitter (2) detects the vehicle speed, and transmits the frame after a predetermined time has elapsed since the vehicle speed reached the first predetermined speed. In the receiver (3), vehicle speed information is acquired from an electronic control unit that handles vehicle speed information, and it takes from the timing when the vehicle speed reaches the first predetermined speed based on the acquired vehicle speed information to receive a frame. The time interval is calculated, and whether or not this time interval matches the information on the elapsed time included in the frame is checked. Based on the comparison result, the transmission frame from each transmitter (2) of the own vehicle and the transmission frame from another vehicle can be discriminated, and the identification information of each transmitter (2) of the own vehicle is accurately registered. be able to. And based on the registered identification information, it becomes possible to discriminate | determine more correctly the signal transmitted from the transmitter (2) attached to the wheel of the own vehicle, and the signal transmitted from the other vehicle.

  In the invention according to claim 2, when the receiver (3) has not registered four pieces of identification information of the transmitter (2), or the frame in which the four registered identification information is stored. When the vehicle cannot be received for a certain period of time, it automatically switches to the identification information registration mode in order to perform the own vehicle signal discrimination process.

  Thus, when the identification information of four transmitters (2) is not registered as in the initial registration, or when one or more transmitters (2) of the four wheels are replaced When the transmission frame from each of the transmitters (2) of the four wheels where the identification information is registered cannot be received for a certain period of time, the own vehicle signal discrimination processing is performed by automatically switching to the identification information registration mode. Can do.

  In the invention according to claim 3, the receiver (3) determines that there is a side-by-side vehicle when there are eight received frames in which the traveling pattern obtained from the frame matches the traveling pattern of the host vehicle. It is characterized by registering eight pieces of identification information and deleting only four pieces of identification information of the host vehicle by deleting the four pieces of identification information that have not been received when the frame has not been received for a certain period of time. Yes.

  As described above, when there are eight received frames in which the traveling pattern obtained from the frame matches the traveling pattern of the host vehicle, there is a parallel vehicle that performs the same operation other than the host vehicle. 8 identification information is registered. If there is an unreceived frame for a certain period of time, the four identification information that has not been received among the eight registered identification information is deleted, and the four identification information that has been continuously received is automatically deleted. Leave as the vehicle transmitter (2). This makes it possible to accurately identify and register the transmitter (2) of the own vehicle even if there is a parallel running vehicle, and based on the registered identification information, the transmission frame of the transmitter (2) of the own vehicle and the like. It is possible to discriminate the transmission frame from the vehicle.

  In the invention according to claim 4, when the receiver (3) has five or more and less than eight of the received frames whose traveling pattern obtained from the frame matches the traveling pattern of the host vehicle. , Registering 5 or more and less than 8 identification information on the assumption that there is a parallel running vehicle, monitoring frames received during a certain period thereafter, and only 4 frames that match the running pattern of the vehicle If it cannot be received, the four pieces of identification information are left as identification information of the transmitter (2) of the own vehicle, and if the number is five or more and less than eight within a certain time, the alarm unit (4) is used. The transmitter (2) is alerted that there is a possibility of failure.

  In this way, when there are five or more and less than eight traveling patterns obtained from the frame that coincide with the traveling pattern of the host vehicle, identification information is registered for that number, and registered for a certain period of time. It is monitored whether or not only the specified number of frames are received, and if the number is 5 or more and less than 8 even after the predetermined time has elapsed, the transmitter (2) may be out of order. Warning. In this way, when the transmitter (2) of the host vehicle is replaced, when the transmitter (2) is out of order, the failure of the transmitter (2) can be accurately detected. It is possible to warn the driver. As a result, for example, it is possible to comply with laws and regulations that require a warning if the transmitter (2) fails.

  In the first or fourth aspect, the present invention is shown as the own vehicle signal discriminating device. However, as shown in the fifth aspect, the own vehicle signal discriminating device can be incorporated in the tire air pressure detecting device. That is, the transmitter (2) includes a sensing unit (21) that outputs a detection signal corresponding to the tire pressure provided on each of the four wheels (5a to 5d), and is sensed by the first control unit (22). The tire pressure information obtained by signal processing of the detection signal of the unit (21) is stored in a frame, and then the frame is transmitted to the transmitter (3). In the receiver (3), the second control unit (34) From the information relating to the tire pressure, it is possible to detect the air pressure of the tires provided on the four wheels (5a to 5d).

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

1 is a diagram illustrating an overall configuration of a tire air pressure detection device to which a host vehicle signal discrimination device according to a first embodiment of the present invention is applied. 2 is a block diagram showing a transmitter 2 and a receiver 3. FIG. It is the figure which showed the waveform of the detection signal of the acceleration sensor. It is the figure which showed an example of the relationship between the detection signal of the acceleration sensor 22 and the frame transmission after the vehicle speed reaches the first predetermined speed. It is the schematic diagram which showed the mode when it was out of order, when the transmitter 2 of all four wheels 5a-5d was replaced | exchanged newly, and when the transmitter 2 was replaced | exchanged only for one wheel. It is the figure which showed an example of the relationship between the detection signal of the acceleration sensor 22 demonstrated in 2nd Embodiment of this invention, the threshold value set according to a vehicle speed, and frame transmission.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a tire air pressure detection device to which a host vehicle signal discrimination device according to a first embodiment of the present invention is applied. The left direction in FIG. 1 corresponds to the front of the vehicle 1, and the right direction in FIG. 1 corresponds to the rear of the vehicle 1. With reference to this figure, the tire pressure detecting device in the present embodiment will be described.

  As shown in FIG. 1, the tire air pressure detection device is attached to a vehicle 1 and includes a transmitter 2, a receiver 3, and a display 4.

  As shown in FIG. 1, the transmitter 2 is attached to each wheel 5 a to 5 d in the vehicle 1, and detects the air pressure of the tire attached to the wheels 5 a to 5 d and relates to the tire air pressure indicating the detection result. Information is stored in a frame and transmitted. The receiver 3 is attached to the vehicle body 6 side of the vehicle 1 and receives a frame transmitted from the transmitter 2 and performs various processes and calculations based on the detection signal stored therein. Wheel position detection and tire pressure detection. FIG. 2 shows a block configuration of the transmitter 2 and the receiver 3.

  As shown in FIG. 2A, the transmitter 2 includes a sensing unit 21, an acceleration sensor 22, a microcomputer 23, a transmission circuit 24, and a transmission antenna 25, and supplies power from a battery (not shown). Each part is driven based on the above.

  The sensing unit 21 includes, for example, a diaphragm type pressure sensor 21a and a temperature sensor 21b, and outputs a detection signal corresponding to the tire pressure and a detection signal corresponding to the temperature. The acceleration sensor 22 corresponds to vehicle speed detection means for detecting the vehicle speed of the wheels 5a to 5d to which the transmitter 2 is attached. The acceleration sensor 22 of the present embodiment outputs detection signals corresponding to accelerations in both directions perpendicular to the circumferential direction of the wheels 5a to 5d among the accelerations acting on the wheels 5a to 5d when the wheels 5a to 5d rotate.

  The microcomputer 23 is a well-known one having a control unit (first control unit) and the like, and executes predetermined processing according to a program stored in a memory in the control unit. Individual ID information including identification information unique to the transmitter for identifying each transmitter 2 and identification information unique to the vehicle for identifying the host vehicle is stored in the memory in the control unit.

  The microcomputer 23 receives the detection signal related to the tire pressure from the sensing unit 21, processes the signal and processes it as necessary, and stores the information related to the tire pressure in the frame together with the ID information of each transmitter 2. . The microcomputer 23 monitors the detection signal of the acceleration sensor 22 and detects the vehicle speed from the wheels 5a to 5d to which the transmitters 2 are attached. When the microcomputer 23 creates a frame, the microcomputer 23 performs frame transmission (data transmission) from the transmission antenna 25 to the receiver 3 via the transmission circuit 24 based on the result of vehicle speed detection.

  Specifically, the microcomputer 23 performs frame transmission on the condition that the vehicle speed is equal to or higher than a first predetermined speed (for example, 20 km / h) and starts transmission for a predetermined time after the vehicle speed reaches the first predetermined speed. After the elapse of time, the frame transmission is performed after storing the information of the elapsed time from the arrival at the first predetermined speed to the transmission within the frame. Thereafter, periodic transmission, that is, frame transmission is performed at regular intervals. Thus, since the frame transmission start timing is set based on the time when the vehicle speed reaches the first predetermined speed, the microcomputer 23 uses the detection signal of the acceleration sensor 22 to detect the vehicle speed. Yes. FIG. 3 is a diagram showing a waveform of a detection signal of the acceleration sensor 22. As shown in this figure, the output of the acceleration sensor 22 includes gravity acceleration and acceleration based on centrifugal force (centrifugal acceleration). It is possible to calculate the vehicle speed by extracting the centrifugal acceleration from this, integrating the centrifugal acceleration and multiplying the coefficient. For this reason, the microcomputer 23 calculates the centrifugal acceleration by removing the gravitational acceleration component from the output of the acceleration sensor 22, and calculates the vehicle speed based on the centrifugal acceleration.

  The time from when the vehicle speed reaches the first predetermined speed until frame transmission may be the same for each transmitter 2, but it can be received by the receiver 3 by radio wave interference from a plurality of transmitters 2. In order to prevent the loss, it is preferable to set a different time by providing a random delay for each transmitter 2. In addition, the speed obtained based on the detection signal of the acceleration sensor 22 is actually the wheel speed, but the wheel speed and the vehicle speed almost coincide with each other if the speed is low enough to be used as a frame transmission condition. The speed is considered as the vehicle speed.

  The transmission circuit 24 functions as an output unit that transmits a frame transmitted from the microcomputer 23 to the receiver 3 through the transmission antenna 25. For frame transmission, for example, radio waves in the RF band are used.

  The transmitter 2 configured in this way is attached to an air injection valve in each of the wheels 5a to 5d, for example, and is arranged so that the sensing unit 21 is exposed inside the tire. Accordingly, the corresponding tire pressure is detected, and as described above, when a predetermined time has elapsed after the vehicle speed exceeds the first predetermined speed, the wheel position is detected through the transmission antenna 25 provided in each transmitter 2. Perform frame transmission. Thereafter, the transmitter 2 periodically transmits a signal related to tire air pressure to the receiver 3 side by performing frame transmission at regular intervals (for example, every minute). At this time, for example, by providing a random delay for each transmitter 2, the transmission timing of each transmitter 2 is shifted.

  As shown in FIG. 2B, the receiver 3 includes a receiving antenna 31, a receiving circuit 32, a microcomputer 33, and the like.

  The receiving antenna 31 is for receiving a frame transmitted from each transmitter 2. The receiving antenna 31 is fixed to the vehicle body 6. The reception antennas 31 may be provided in a number corresponding to each transmitter 2, or for receiving transmission frames from the transmitter 2 of both front wheels 5a and 5b and transmitting from the transmitter 2 of both rear wheels 5c. Although two frames may be used for receiving a frame, in the present embodiment, the antenna is a shared antenna that can receive the transmission frames of the transmitters 2 of all the wheels 5a to 5d.

  The receiving circuit 32 functions as an input unit that receives a transmission frame from each transmitter 2 received by the receiving antenna 31 and sends the frame to the microcomputer 33.

  The microcomputer 33 corresponds to the second control unit, and executes the own vehicle signal determination process according to a program stored in a memory in the microcomputer 33. Specifically, the microcomputer 33 automatically switches to the ID registration mode when performing the own vehicle signal discrimination process, and handles an electronic control device (for example, handling various data and vehicle speed information stored in the transmission frame). Based on the vehicle speed information from the meter ECU), it is determined whether the frame is a transmission frame from the transmitter 2 of the own vehicle or a transmission frame from another vehicle. The microcomputer 33 registers the ID information by storing the ID information stored in the frame determined to be transmitted from each transmitter 2 of the host vehicle.

  Further, when the microcomputer 33 subsequently receives a frame, it determines whether it is a transmission frame from each transmitter 2 of the own vehicle or a transmission frame from another vehicle based on the registered ID information. And if it is the transmission frame from each transmitter 2 of the own vehicle, based on the information regarding the tire air pressure stored in the transmission frame, the tire air pressure detection of each wheel 5a-5d is performed, and according to the tire air pressure An electric signal is output to the display 4. For example, the microcomputer 33 detects a decrease in tire air pressure by comparing the tire air pressure with a predetermined threshold Th, and outputs a signal to that effect to the display 4 when a decrease in tire air pressure is detected. As a result, if the tire air pressure drops in any one of the four wheels 5a to 5d, this is transmitted to the display 4.

  The display device 4 functions as an alarm unit, and as shown in FIG. 1, is arranged at a place where the driver can visually recognize, and is configured by, for example, a meter display or the like installed in an instrument panel in the vehicle 1. The For example, when a signal indicating that the tire air pressure has decreased is sent from the microcomputer 33 in the receiver 3, the display device 4 notifies the driver of the decrease in tire air pressure by displaying that effect.

  In FIG. 2B, it is assumed that the indicator 4 is configured by a meter provided in the instrument panel, and a signal indicating that the tire air pressure has decreased is sent to the meter ECU. Thus, the case where the display 4 displays that effect is shown. In this case, since the vehicle speed information is handled by the meter ECU as described above, the microcomputer 33 can acquire the vehicle speed information from the meter ECU.

  Next, the operation of the tire pressure detection device of the present embodiment will be described. Hereinafter, the operation of the tire air pressure detection device will be described, but the operation will be divided into the operation of the own vehicle signal discrimination device provided in the tire air pressure detection device and the operation at the time of tire air pressure detection.

  The own vehicle signal discriminating device is composed of the transmitter 2 and the receiver 3 among the tire pressure detecting devices described above, and the receiver 3 handles the transmission frame and the vehicle speed information from the transmitter 2. To determine whether the frame is a transmission frame from the transmitter 2 of the own vehicle or a transmission frame from another vehicle based on the vehicle speed information.

  First, the transmitter 2 performs acceleration detection by performing acceleration detection by the acceleration sensor 22 for each predetermined sampling period. The vehicle speed is detected based on the detection signal of the acceleration sensor 22, and when the vehicle speed reaches a first predetermined speed (for example, 20 km / h), each transmitter 2 is detected by the sensing unit 21 at that time and its ID information. The information on the tire pressure and the information on the elapsed time from when the vehicle speed reaches the first predetermined speed until it is transmitted are stored in the frame. Then, the frame is transmitted after a predetermined time has elapsed since the vehicle speed reached the predetermined vehicle speed. For reference, FIG. 4 shows an example of the relationship between the detection signal of the acceleration sensor 22 and the vehicle speed reaching the first predetermined speed until frame transmission is performed.

  On the other hand, for example, when the ignition switch is switched from OFF to ON, the microcomputer 33 of the receiver 3 determines whether or not the execution condition of the own vehicle signal determination process is satisfied, and satisfies the condition to determine the own vehicle signal determination process. Is automatically switched to the ID registration mode. For example, the microcomputer 33 determines whether the ID registered wheels are less than four as in the initial registration or when one or more transmitters 2 of the four wheels are replaced. When the transmission frames from the registered transmitters 2 of the four wheels cannot be received for a certain period of time, it is assumed that the conditions for executing the own vehicle signal determination process are satisfied. As described above, since the mode automatically switches to the ID registration mode when a predetermined condition is satisfied, the ID registration mode is automatically set without manual operation using an ID registration switch or tool. Can be switched to.

  Then, the microcomputer 33 acquires vehicle speed information from an electronic control device that handles vehicle speed information such as a meter ECU, and based on the vehicle speed information included in the received frame and the vehicle speed information acquired from the electronic control device. Then, it is verified whether or not the running patterns are the same. For example, the received frame includes information on the elapsed time from when the vehicle speed reaches the first predetermined speed until frame transmission is performed. For this reason, the microcomputer 33 calculates the time interval required from the timing when the vehicle speed reaches the first predetermined speed to the reception of the frame based on the acquired vehicle speed information, and this time interval is included in the frame. The traveling pattern is collated by collating whether or not the information matches the elapsed time information. If the traveling patterns of the received frames match, the ID information stored in the frame is assumed to be the transmission frame of the transmitter 2 attached to the wheels 5a to 5d of the host vehicle. Register ID as vehicle.

  In this way, the ID registration of each transmitter 2 of the own vehicle can be performed, and even if a frame of another vehicle is received, the ID information included in the frame matches the ID registration performed. By determining whether or not, it is possible to determine that it is not a transmission frame of the transmitter 2 of the host vehicle.

  However, when there is a parallel vehicle in the ID registration mode, the receiver 3 of the own vehicle receives the transmission frame of the parallel vehicle, and the traveling pattern of the parallel vehicle matches the traveling pattern of the own vehicle. There is a possibility. Specifically, as described above, when the number of registered wheels is less than four as in the initial registration, or when one or more transmitters 2 of the four wheels are replaced. As described above, when the transmission frames from the transmitters 2 of the four wheels whose IDs are registered cannot be received for a certain period of time, the execution condition of the own vehicle signal determination process is satisfied. For this reason, in the situation where these execution conditions are satisfied, the following processing is performed in consideration of the case where a parallel running vehicle exists. FIG. 5 shows, for example, a state in which all transmitters 2 of four wheels 5a to 5d are newly replaced and a case in which only one wheel is replaced with a transmitter 2 is out of order. Will be described with reference to FIG.

  First, as shown in FIG. 5 (a), when all the transmitters 2 of the four wheels 5a to 5d are newly replaced, the traveling pattern obtained from the received frame is the traveling pattern of the host vehicle. There are eight or more that match the pattern. In this case, it is assumed that there is a parallel vehicle performing the same operation other than the own vehicle, and eight pieces of ID information are registered. Further, the tire pressure is monitored from the information related to the tire pressure stored in the frames of the eight IDs, and the non-reception of the frame is monitored.

  If four frames have not been received for a certain period of time, the ID registration mode is entered again, and four ID information that has not been received out of the eight registered ID information is deleted and continuously received. The remaining four ID information is left in the ID registration as that of the transmitter 2 of the own vehicle. As described above, when four ID registrations are left, it is considered that each transmitter 2 of the host vehicle has not failed, and thus the ID registration is terminated without warning.

  On the other hand, if eight frames of ID information can be received after a certain period of time, the eight ID information remains registered. In this case, the ID information of the transmitter 2 of the host vehicle and the side-by-side vehicle cannot be discriminated, but it is considered that at least the transmitter 2 has not failed. For this reason, in this case as well, warning is not performed, and monitoring for unreceived frames within a certain time is continued.

  The ID registration mode that satisfies the conditions for executing the own vehicle signal discrimination process is entered when the number of registered wheels is less than four as in the initial registration, or when one or more of the four wheels are registered. This is a case where transmission frames from the transmitters 2 of the four wheels whose IDs are registered cannot be received for a certain period of time as when the transmitter 2 is exchanged. For this reason, the ID registration mode is not entered if a frame including four registered ID information is periodically received. However, when the transmitter 2 is replaced due to a failure or the like, the execution condition of the own vehicle signal discrimination process is satisfied and the ID registration mode is entered. In this case, the parallel running vehicle performing the same operation as the own vehicle is performed. If it exists, the ID information of the parallel running vehicle may be registered incorrectly.

  On the other hand, when there are eight items whose traveling pattern matches the traveling pattern of the own vehicle as in the present embodiment, the eight ID information of the own vehicle and the side-by-side vehicle is registered, and the fixed time frame When the non-reception continues, four of the eight ID information are deleted. This makes it possible to accurately register the ID of the transmitter 2 of the own vehicle even if there is a parallel running vehicle. Based on the ID information registered in the ID, the transmission frame of the transmitter 2 of the own vehicle and the other vehicle can be registered. The transmission frame can be discriminated.

  Further, as described above, the microcomputer 33 according to the present embodiment, when there are eight received frames in which the traveling pattern obtained from the frame matches the traveling pattern of the own vehicle, Eight pieces of ID information are registered on the assumption that there are side-by-side vehicles performing the same operation other than the vehicle. However, for example, as shown in FIG. 5B, when the transmitter 2 is exchanged for only one wheel and there is a failure, eight pieces of ID information are not prepared. For this reason, when the number of travel patterns obtained from the frame matches the travel pattern of the host vehicle is 5 or more and less than 8, ID registration is performed for that number.

  Even in such a case, the frames received during a certain time thereafter are monitored, and if only four frames of ID information can be received during the certain time, the received four ID information is stored in the own vehicle. Of the transmitter 2 is left in the ID registration. If only frames of ID information of 5 or more and less than 8 can be received within a certain time, it is considered that the number of ID information for two vehicles is insufficient. That is, if there is a parallel vehicle, a frame including eight ID information of the own vehicle and the parallel vehicle should be received, and if it is less than eight, either the own vehicle or the parallel vehicle is transmitted. The machine 2 may be out of order. For this reason, the microcomputer 33 outputs a signal indicating that there is a possibility that the transmitter 2 has failed to the display 4, and the display 4 gives a warning to that effect.

  In this way, when the transmitter 2 of the host vehicle is replaced, when the transmitter 2 is out of order, the failure of the transmitter 2 can be accurately detected, and this is sent to the driver. It is possible to warn. Of course, it is also conceivable that not the transmitter 2 of the own vehicle but the transmitter of another vehicle is out of order. However, at least when there is a possibility of failure of the transmitter 2 of the own vehicle, a warning to that effect can be given. If there is no failure, the four ID information of each transmitter 2 of the own vehicle is obtained when the vehicle travels again. Since ID registration is performed, it is preferable in terms of safety to employ such a warning method.

  Thus, when ID registration by the own vehicle signal discrimination process is completed, frames for four wheels are received by the receiver 3 each time a frame is transmitted from each transmitter 2 at regular intervals. . Based on the ID information stored in each frame, it is determined whether the frame is a transmission frame from the transmitter 2 of the own vehicle or a transmission frame from another vehicle, and the tire air pressure included in the transmission frame from the transmitter 2 of the own vehicle It becomes possible to detect the tire pressure of each wheel 5a-5d from the information regarding.

  As described above, in the own vehicle signal determination process, the transmitter 2 detects the vehicle speed, and transmits the frame after a predetermined time has elapsed since the vehicle speed reached the first predetermined speed. The receiver 3 acquires vehicle speed information from an electronic control device that handles vehicle speed information, and the time taken from the timing when the vehicle speed reaches the first predetermined speed based on the acquired vehicle speed information to receive a frame. While calculating the interval, it is checked whether or not this time interval matches the information of the elapsed time included in the frame. Based on this comparison result, the transmission frame from each transmitter 2 of the own vehicle and the transmission frame from another vehicle can be discriminated, and the ID registration of each transmitter 2 of the own vehicle can be performed accurately. Based on the registered ID information, it is possible to more accurately discriminate between a signal transmitted from the transmitter 2 attached to the wheel of the host vehicle and a signal transmitted from another vehicle.

  In addition, when there are eight received frames in which the traveling pattern obtained from the frame matches the traveling pattern of the host vehicle, there is a side-by-side vehicle that performs the same operation other than the host vehicle. Therefore, eight pieces of ID information are registered. Then, if there is a frame that has not been received for a certain period of time, it enters the ID registration mode again, deletes four ID information that has not been received from the eight registered ID information, and is continuously received. The remaining four ID information is left in the ID registration as that of the transmitter 2 of the own vehicle. This makes it possible to accurately register the ID of the transmitter 2 of the own vehicle even if there is a parallel running vehicle. Based on the ID information registered in the ID, the transmission frame of the transmitter 2 of the own vehicle and the other vehicle can be registered. The transmission frame can be discriminated.

  Furthermore, when the number of travel patterns obtained from the frame matches the travel pattern of the host vehicle is 5 or more and less than 8, ID registration is performed for that number, and the number of ID registrations for a certain period of time. If the number of frames is less than 8 even after a predetermined time has elapsed, a warning is given that there is a possibility that the transmitter 2 has failed. In this way, when the transmitter 2 of the host vehicle is replaced, when the transmitter 2 is out of order, the failure of the transmitter 2 can be accurately detected, and this is sent to the driver. It is possible to warn. As a result, for example, it is possible to comply with laws and regulations that require a warning when the transmitter 2 fails.

(Second Embodiment)
A second embodiment of the present invention will be described. In this embodiment, the sampling period of the acceleration sensor 22 by the transmitter 2 is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment, and therefore different from the first embodiment. Only will be described.

  In the above embodiment, the case where the sampling period of the acceleration sensor 22 by each transmitter 2 is set to a constant period has been described, but the sampling period may be changed according to the vehicle speed.

  FIG. 6 is a diagram illustrating an example of a relationship between a detection signal of the acceleration sensor 22 according to the present embodiment, a threshold set according to the vehicle speed, and frame transmission.

  In order to suppress current consumption, the transmitter 2 performs vehicle speed detection based on the detection signal of the acceleration sensor 22 at a sampling frequency that is usually infrequent (for example, 16 s / time). However, if the sampling period is long, the variation in the timing at which the vehicle speed is detected to reach the predetermined vehicle speed becomes large. For this reason, as shown in FIG. 6, when the vehicle speed reaches a second predetermined speed (for example, 10 km / h) lower than the first predetermined speed which is a frame transmission condition, the sampling period of the acceleration sensor 22 is set to a second predetermined speed. The vehicle speed is detected at a high frequency (for example, 0.5 s / time) so that the vehicle speed is detected at a high frequency. When the vehicle speed reaches the first predetermined speed, which is a frame transmission condition, the sampling cycle in the acceleration sensor 22 is restored again.

  In this way, it is possible to more accurately detect that the vehicle speed reaches the first predetermined speed while improving the battery life by suppressing the current consumption. Therefore, it is possible to prevent a variation in timing at which it is detected that the vehicle speed has reached the predetermined vehicle speed between the transmitters 2 from increasing.

  When the sampling speed of the acceleration sensor 22 is increased when the vehicle speed reaches the second predetermined speed as described above, the vehicle speed is consumed until the vehicle speed reaches the first predetermined speed that is the transmission condition of the transmission frame. The current increases. For this reason, for example, the state of centrifugal acceleration = 0 from the detection signal of the acceleration sensor 22, that is, the stop state of the vehicle is detected, and only when the stop state has passed for a predetermined time (for example, 10 minutes) or more, the sampling frequency is high. It is preferable to change to a form in which acceleration is detected. Thereby, only when there is a possibility that tire replacement or transmitter 2 replacement has been performed, it is possible to change to a form in which acceleration is detected with a high frequency sampling cycle, and while obtaining the above effect, more current consumption It is also possible to suppress this.

(Third embodiment)
A third embodiment of the present invention will be described. In the present embodiment, the discrimination between the transmission frame from the transmitter 2 of the own vehicle and the transmission frame from the side-by-side vehicle is performed based on the reception intensity (RSSI value) with respect to the first embodiment. Since other aspects are the same as those in the first embodiment, only portions different from those in the first embodiment will be described.

  In the above embodiment, when a transmission frame is received from a side-by-side vehicle that performs the same operation as that of the host vehicle, eight pieces of ID information are registered as IDs. By deleting four from one ID information, ID registration of each transmitter 2 of the own vehicle can be performed. However, the transmission frame from the transmitter 2 of the own vehicle and the transmission frame from the side-by-side vehicle can be determined by other methods.

  Specifically, the receiver 3 is provided with intensity measuring means for measuring the reception intensity of each transmission frame. If the measured reception intensity is smaller than a predetermined threshold value, the signal from other vehicles located far from the receiver 3 is received. The transmission frame may be excluded from the ID registration. In this way, the transmission frame from the transmitter 2 of the own vehicle and the transmission frame from the parallel vehicle can be discriminated earlier. Of course, depending on the traveling situation, there is a possibility that the reception intensity of the transmission frame from the parallel vehicle becomes a large value. In that case, as described in the first embodiment, eight ID information is registered as IDs, and when four frames are not received for a certain period of time, four are deleted from the eight ID information. It ’s fine.

(Other embodiments)
In each of the above-described embodiments, frame transmission is performed when a predetermined time has elapsed since the vehicle speed becomes equal to or higher than a predetermined vehicle speed (for example, 20 km / h), and the elapsed time from when the vehicle speed reaches the first predetermined speed in the frame until transmission is performed. Information is stored. On the other hand, when the vehicle is reduced to a third predetermined speed lower than the first predetermined speed after the vehicle has exceeded the first predetermined speed, it takes from the time the vehicle exceeds the first predetermined speed to the third predetermined speed. The change in the detection signal of the acceleration sensor 22 after the vehicle time reaches the first predetermined speed can be stored in the frame. In this way, by storing in the frame other than the information on the elapsed time from when the vehicle speed reaches the first predetermined speed until it is transmitted, it is used for checking whether or not it matches the traveling pattern of the host vehicle. Information can be increased and more accurate collation is possible.

  In the above embodiment, since the own vehicle signal discriminating device is applied to the tire air pressure detecting device, information on the elapsed time from when the vehicle speed reaches the first predetermined speed until it is transmitted is stored in the frame and transmitted. I have to. Thereby, the own vehicle signal discrimination process and the tire air pressure detection can be performed in the common frame. However, this is merely an example of the frame, and the frame for performing the vehicle signal determination process and the frame for storing information related to the tire air pressure may be separate frames.

  In the above embodiment, the receiver 3 obtains the vehicle speed information from the electronic control device, calculates the time interval taken from when the vehicle speed reaches the first predetermined speed until the frame is received, and The elapsed time from the reaching of the first predetermined speed stored in the frame to the frame transmission is collated. The collation at this time is preferably completely coincident, but since there is some variation, the collation may be performed with a certain range of error expected.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Transmitter 3 Receiver 4 Indicator 5 (5a-5d) Wheel 6 Car body 21 Sensing part 22 Acceleration sensor 23 Microcomputer 24 Transmission circuit 25 Transmission antenna 31 Reception antenna 32 Reception circuit 33 Microcomputer

Claims (5)

Applied to a vehicle (1) to which four wheels (5a-5d) with tires are attached to the vehicle body (6);
A transmitter (2) provided on each of the four wheels (5a to 5d) and having a first control unit (23) that creates and transmits a frame including unique identification information;
The frame provided on the vehicle body (6) side receives a frame transmitted from the transmitter (2) via a receiving antenna (31), and inputs the frame received by the receiving antenna (31) to receive the frame Is transmitted from the transmitter (2) of the host vehicle attached to any of the four wheels (5a to 5d), and the transmitter (2) of the host vehicle is verified. A receiver (3) having a second control unit (35) for executing a vehicle signal discrimination process for registering and storing the identification information of the transmitter (2) Prepared,
The transmitter (2) provided on each of the four wheels (5a to 5d) includes vehicle speed detection means (22) for detecting a vehicle speed based on rotation of the attached wheel, and the vehicle speed detection means (22 After the vehicle speed detected at (1) has reached the first predetermined speed, information on the elapsed time from when the vehicle speed reaches the first predetermined speed until frame transmission is stored in the frame after the predetermined time has elapsed. Send
The receiver (3) has vehicle speed information acquisition means for acquiring vehicle speed information from an electronic control unit having vehicle speed information, and after the vehicle speed reaches a first predetermined speed from the vehicle speed information acquired from the vehicle speed information acquisition means. Checking whether or not it matches the traveling pattern of the host vehicle based on the time interval taken to receive the frame and the elapsed time from reaching the predetermined vehicle speed stored in the frame to frame transmission Then, it is verified whether or not the frame is transmitted from the transmitter (2) of the own vehicle attached to any of the four wheels (5a to 5d). Signal discrimination device.   When the receiver (3) has not registered four pieces of identification information of the transmitter (2) or when a frame in which the four registered identification information is stored cannot be received for a certain period of time, The own vehicle signal discriminating apparatus according to claim 1, wherein the own vehicle signal discriminating apparatus is automatically switched to an identification information registration mode in order to perform the own vehicle signal discriminating process.   The receiver (3) determines that there is a side-by-side vehicle when there are eight of the received frames in which the traveling pattern obtained from the frame matches the traveling pattern of the host vehicle. 2 is registered, and only four pieces of identification information of the host vehicle are left by deleting four pieces of identification information that have not been received when the frame has not been received for a certain period of time. Or the own vehicle signal discrimination device of 2.   When the receiver (3) has five or more and less than eight traveling patterns obtained from the received frames that match the traveling pattern of the host vehicle, 5 or more and less than 8 pieces of identification information are registered, and frames received during a certain period thereafter are monitored. If only 4 frames matching the traveling pattern of the host vehicle can be received, Four pieces of identification information are left as identification information of the transmitter (2) of the host vehicle, and if the number is five or more and less than eight during a certain time, the transmission is performed via the alarm unit (4). 4. The own vehicle signal discriminating device according to any one of claims 1 to 3, wherein a warning is given that there is a possibility that the machine (2) is out of order. A tire pressure detecting device including the own vehicle signal discriminating device according to any one of claims 1 to 4,
The transmitter (2) includes a sensing unit (21) that outputs a detection signal corresponding to the tire pressure provided on each of the four wheels (5a to 5d), and the first control unit (22). After storing the information on the tire air pressure obtained by signal processing the detection signal of the sensing unit (21) in a frame, the frame is transmitted to the transmitter (3),
The receiver (3) detects the air pressure of the tires provided on the four wheels (5a to 5d) from the information on the tire air pressure in the second controller (34). A tire air pressure detecting device.

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